Reinforced membranes, process and apparatus for making them, and use thereof as ion-exchange membranes in chlor-alkali cells or as catalysts

摘要

Reinforced membranes comprise at least two layers of melt-fabricable fluorinated polymer having side chains containing sulfonyl and/or carboxyl groups in melt fabricable form, and a woven reinforcing fabric comprising warp and weft strands, there being at least one layer of said fluorinated polymer on each side of said reinforcing fabric, the warp and weft strands of said reinforcing fabric defining windows between said strands, each layer of fluorinated polymer over at least 70% of the area in each of at least 90% of said windows being of uniform thickness within plus or minus 10%. lon-exchange membranes can be derived therefrom by converting the sulfonyl and/or carboxyl groups to ion exchange form.;Such reinforced membranes can be prepared by (1) continuously bringing at least two films of mettfabricable fluorinated polymer and a web of reinforcing material into face-to-face contact such that proximate surfaces of two of said films contact opposite planar surfaces of said web, and moving the resulting combination of said films and said web vertically, unsupported except at two opposite edges thereof, (2) removing air from between said films at the two opposite edge portions thereof, (3) applying heat to the two outermost opposite planar film surfaces, first in the center portions thereof and progressively moving toward and including the edge portions thereof, and (4) cooling the resulting reinforced membrane.;Apparatus for making reinforced membranes comprises